docs: def getAllClasses(self, hide_base_schemas=True, hide_implicit_types=True):
          """
          * hide_base_schemas: by default, obscure all RDF/RDFS/OWL/XML stuff
          * hide_implicit_types: don't make any inference based on rdf:type declarations
          """
          query = """SELECT DISTINCT ?x ?c
                   WHERE {
                           {
                               { ?x a owl:Class }
                               union
                               { ?x a rdfs:Class }
                               union
                               { ?x rdfs:subClassOf ?y }
                               union
                               { ?z rdfs:subClassOf ?x }
                               union
                               { ?y rdfs:domain ?x }
                               union
                               { ?y rdfs:range ?x }
                               %s
                           } .
  
                           OPTIONAL { ?x a ?c } 
                           # get the type too if available
  
                      %s
  
                   }
                   ORDER BY  ?x
                   """
  
          BIT_BASE_SCHEMAS = """FILTER(
                       !STRSTARTS(STR(?x), "http://www.w3.org/2002/07/owl")
                       && !STRSTARTS(STR(?x), "http://www.w3.org/1999/02/22-rdf-syntax-ns")
                       && !STRSTARTS(STR(?x), "http://www.w3.org/2000/01/rdf-schema")
                       && !STRSTARTS(STR(?x), "http://www.w3.org/2001/XMLSchema")
                       && !STRSTARTS(STR(?x), "http://www.w3.org/XML/1998/namespace")
                       && (!isBlank(?x))
                        ) ."""
          BIT_IMPLICIT_TYPES = """union
                               { ?y rdf:type ?x }"""
  
          if hide_base_schemas == False:  # ..then do not filter out XML stuff
              BIT_BASE_SCHEMAS = ""
          if hide_implicit_types == True:  # .. then do not add extra clause
              BIT_IMPLICIT_TYPES = ""
  
          query = query % (BIT_IMPLICIT_TYPES, BIT_BASE_SCHEMAS)
  
          # print(query)
  
          qres = self.rdflib_graph.query(query)
          return list(qres)